"This new agreement represents a major expansion in trade opportunities in Southeast Asia," Peters said in a news release.

The U.S.-Vietnam aviation agreement reached in October 2003 permitted an unlimited number of all-cargo carriers to operate without limits on the number of flights between the two countries, she said. The agreement reached Tuesday remove restrictions on routing and on carrying cargo to or from third countries.

It also permits U.S. airlines to carry cargo between Vietnam and third countries without requiring a stop in the United States, she added.

Peters also announced Tuesday the United States and Armenia reached a full Open-Skies agreement, the first aviation accord between the two countries. An Open Skies treaty establishes a program of unarmed aerial surveillance flights over the entire territory of its participants.